This specification covers staple or continuous filament carbon/graphite yarn valve stem compression packing, suitable for use as end-rings on packing systems for valves. Intended services include steam, hydrocarbons, water and non-oxidizing chemicals. The material shall be of the following types, classes, and grades: Type I, type II, and Type III; Class 1; Class 2; and Class 3; and Grade A and Grade B. The following tests shall be performed: size; mass; carbon assay; ash content; specific gravity; moisture content; detrimental materials tests; analysis of PTFE coating; compression recovery; and braid geometry retention.

1.1 This specification covers staple or continuous filament carbon/graphite yarn valve stem compression packing, suitable for use as end-rings on packing systems for valves. Intended services include steam, hydrocarbons, water and non-oxidizing chemicals. Where this specification is invoked as ASTM F 2191, Sections 1-18 apply. Where this specification is invoked as ASTM/DoD F 2191, Sections 1-18 and the Supplementary Requirements are applicable.

1.2 The values stated in SI units are to be regarded as the standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.